Cut each plum tomato in half lengthwise, then cut each half into 3 sections lengthwise. Place the tomato sections, skin side down and evenly spaced, on a baking sheet lined with parchment paper. Season lightly with salt and pepper. Place the tomatoes in the preheated oven and roast for 3 hours. Remove from the oven and allow to cool to room temperature. Chop the tomatoes into 1/4-inch pieces. In a 3-quart stainless steel bowl, vigorously whisk together the olive oil with the red wine vinegar. Add the tomatoes and thyme, and stir to combine. Adjust the seasoning, cover tightly with plastic wrap, and set aside at room temperature until needed.

Prepare The Ratatouille

Preheat the oven to 325 degrees Fahrenheit.

Place the garlic in a pie tin or small baking dish, sprinkle with 1/2 tablespoon of olive oil, and then lightly season with salt and pepper. Cover the pie tin with aluminum foil. Place in the preheated oven and roast the garlic until tender, about 30 minutes. Remove the garlic from the oven, discard the aluminum foil, and cool to room temperature. When the garlic is cool enough to handle, peel and trim the cloves or use your fingers to squeeze the pulp away from the skin, and then finely chop the pulp.

Heat 11/2 tablespoons of olive oil in a large nonstick saute pan over medium heat. When hot, add the red onion, lightly season with salt and pepper, and saute for 2 minutes, until tender. Add the roasted garlic, zucchini, and yellow squash. Lightly season with salt and pepper, and saute for 3 minutes, stirring frequently. Add the eggplant, lightly season with salt and pepper, and saute for 2 minutes. Add the tomato cubes, basil, and thyme, and toss to combine. Remove from the heat and transfer the mixture to a 7-quart stainless steel bowl. Add the remaining 1/4 cup of olive oil and stir to combine. Adjust the seasoning with salt and pepper. Cover tightly with plastic wrap and set aside at room temperature for 1 to 2 hours before serving.

Finish And Assemble The Salad

Preheat the oven to 325 degrees Fahrenheit.

Toast the pine nuts on a baking sheet in the preheated oven for 10 minutes. Remove the nuts from the oven and set aside at room temperature until needed.

In a 3-quart stainless steel bowl, combine 2 cups of cold water with the lemon juice. Wash, core, and cut the fennel bulb into very thin strips and immediately place in the acidulated water. (This will help prevent any discoloration as well as crisp the fennel.)

Divide and arrange the watercress, stem ends toward the center, in a ring near the outside edge of four 10- to 12-inch room-temperature plates. Drain the fennel in a colander, rinse under cold running water, and shake dry. Divide and arrange the fennel over the center area of each plate. Whisk the vinaigrette. Dress the watercress and fennel strips on each plate with 2 to 3 tablespoons of the vinaigrette. Place an equal amount of ratatouille on the center of each salad. Dress the ratatouille with 2 to 3 tablespoons of the vinaigrette. Sprinkle 2 tablespoons of pine nuts over each salad. Serve immediately